As demand increases for varying types of applications within mobile telecommunications networks, service providers constantly upgrade their systems in order to reliably provide an expanded functionality. What was once a system designed simply for voice communication has grown into an all-purpose network access point, providing access to a myriad of applications including text messaging, multimedia streaming, and general Internet access. In order to support such applications, providers have built new networks on top of their existing voice networks. As seen in second and third generation networks, voice services must be carried over dedicated voice channels and directed toward a circuit-switched core, while other service communications are transmitted according to the internet protocol (IP) and directed toward a different, packet-switched core. This led to unique problems regarding application provision, metering and charging, and quality of experience (QoE) assurance.
Call drops and call establishment failures are two of the major issues in wireless networks that impact end user experience and cause customer dissatisfaction. As such telecommunication systems become more complex, testing and verification of such systems also increases in complexity. In particular, more test cases are required to exercise various protocol message flows, such as for example, the flow of protocol messages between network elements to establish a call or establish a service between those elements, and in particular, various possible combinations of protocol message sequence that might occur in a real world situation. Thus it is important to be able to test the robustness of network elements to determine if the network elements can gracefully handle receiving incongruous, unexpected or invalid protocol messages. Typical protocol generators used in network test systems only generate protocol compliant messages producing success path responses to protocol messages received from network equipment (network element) under test.
In view of the foregoing, it would be desirable to provide a method to easily introduce failure scenarios in protocol message flows of protocol message based communications systems.